Snowmobiles are known to run on specific snow-covered circuits adapted for exclusive snowmobile circulation. These circuits are sometimes quite elongated, extending in some instances for hundreds of miles. Therefore, these snowmobile circuits must cross public roads once and a while, which are usually made up of gravel or asphalt such abrasive surfaces of the public roads do not bode well for the snowmobiles, whose structure, particularly the front guiding skis, will quickly become worn out when the snowmobiles run frequently thereover.
The state of the art reveals a few patents describing trolleys for lifting above ground a snowmobile when running over public roads. The reader will profitably look at the following references:
(a) U.S. Pat. No. 3,437,354 issued in April 1969 to Edgar Hetteen; PA1 (b) U.S. Pat. No. 3,570,617 issued in March 1971 to Ski Wheels, inc.; PA1 (c) CAN 873,771 issued in June 1971 to Yamaha motor, a Japanese corporation; PA1 (d) U.S. Pat. No. 3,777,829 issued in December 1973 to the Johnson Stamping and Fine Blanking corporation; PA1 (e) U.S. Pat. No. 4,288,087 issued in September 1981 to MPD Enterprises of Delavan, inc.
The above-noted Patents generally describe carriages which may be mounted beneath the front skis of a snowmobile, to rollingly displace the skis over a road. However, a disadvantage of these Patents is that the carriage mounting to the skis does require tools, and does take a substantial time for completing the installation.
That is, to the exception of the U.S. Pat. No. 3,777,829, since various embodiments of carriages are envisioned in FIGS. 2, 3 and 4, which may be easily and quickly mounted, manually, as suggested in FIGS. 7 and 8 of the Patent. More particularly, carriage 38 is mounted beneath the ski 20, bearing on its main body 40, and the ski is frictionally secured thereto between the lateral ears 44 and 68 of the carriage (FIG. 2). A disadvantage of such an installation is the relatively high likelihood of accidental disengagement of the carriage from the ski, Particularly in a curb, since there is no means provided for locking to the ski in operative position, other than the ears 68 and 44 which only in fact hook to the lateral edges of the ski.